1. Technical Field
This patent application relates to secure, collaborative file sharing across trust boundaries and among different devices and users.
2. Background Information
File hosting services that offer cloud storage and file synchronization across multiple client devices are becoming an increasingly popular way to store computer files. These services allow users to create a special folder on a computer, which the service then synchronizes so that it appears to be the same folder with the same contents regardless of the particular device on which the folder is viewed. Files placed in this folder are also accessible through a website and mobile phone applications. Services of this type include Dropbox™, Google™ Drive™, Microsoft™ SkyDrive™, and others. The providers of these services typically offer software for different operating systems such as Microsoft Windows™, Apple™ Mac OSx™, Linux™, Android™, Apple iOS™, Blackberry™ OS™ and web browsers. The popularity of these services is no doubt due to the increasing tendency of each person to use multiple devices such as laptops, desktops, smart phones, tablets, etc. while expecting their information to be available anytime, anywhere.
These services in effect add synchronization and sharing to simple file hosting services. Synchronization supports background distribution of files across the user's various devices, as well as revision management, so that a file edited or deleted on one machine may be recovered from any of the other synced machines. Some of these services also support multiuser version control, enabling several users to edit and repost files without overwriting versions of the same file created by other users.
A number of innovative uses and mashups of these “store and sync” technologies have been developed. For example, add-ons to the Dropbox Service allow users to email files, facilitate online backup using protocols such as File Transfer Protocol (FTP), provide an interface to desktop applications, and include extensions that support file synchronization with other services such as Google Docs.